Synthesis process of chemicals using sugar as a raw material is utilized in the production of various industrial raw materials, and particularly synthesis process of sugar alcohol by a hydrogenation reaction of sugar is the representative example. At present, materials derived from edible raw materials such as sugarcane, starch and sugar beets are industrially used as sugar for the synthesis raw materials. However, because of increases in edible raw material prices due to future increase in the world's population or ethical aspects of competition with edibles, construction of a process of efficiently producing a sugar solution from renewable non-edible resources, that is, a cellulose-containing biomass, or a process of efficiently converting the sugar solution obtained as a synthesis raw material into an industrial raw material is becoming a future problem.
As the conventional technology of obtaining sugar from a cellulose-containing biomass, a method of hydrolyzing cellulose and hemicellulose in a biomass into monosaccharide represented by glucose and xylose using concentrated sulfuric acid (JP-T-11-506934) and a method of performing pretreatment improving hydrolysis reactivity of a cellulose-containing biomass, and then hydrolyzing the biomass by an enzyme reaction are generally known (JP-A-2001-95594). Also, a method of obtaining a sugar solution by purifying a sugar aqueous solution after hydrolysis using an ultrafiltration membrane, a nanofiltration membrane, a reverse osmosis membrane or the like is reported (WO 2013/018694, WO 2009/110374 and WO 2010/067785).
As the technology relating to a method of producing sugar alcohol from sugar derived from a cellulose-containing biomass by a hydrogenation reaction, a method of producing a xylose polymer reduced substance that is sugar alcohol by removing low molecular weight contaminants contained in a xylose polymer-containing aqueous solution obtained by treating a xylan-containing biomass with specific high pressure hot water, from the permeation side of a nanofiltration membrane, and then hydrogenating a xylose polymer collected from the non-permeation side at high temperature under high pressure in the presence of a metal catalyst is known (JP-A-2008-56599).
In a hydrogenation reaction using a metal catalyst, when a substance poisoning a catalyst (catalyst poison) is present, the reaction does not proceed. Therefore, it is required to remove the catalyst poison as possible. Low molecular weight organic substances such as a nitrogen compound, a sulfur compound and a phosphorus compound and metals such as Ag, Hg, Pb, Bi, Sn, Cd and As are known as specific examples of the catalyst poison for a metal catalyst (Catalyst 2015, 5, 145-269). For removal of those catalyst poisons, a method of adsorbing and removing those by performing an activated carbon treatment or an ion-exchanged resin treatment are general (JP-A-2001-79411).
We found that when sugar alcohol is produced from a sugar aqueous solution as a raw material obtained by hydrolysis of a cellulose-containing biomass, a hydrogenation reaction of a sugar alcohol is inhibited by that catalyst poisons contained in the sugar aqueous solution. There is thus a need to provide a method of efficiently producing sugar alcohol from a cellulose-containing biomass by a simple method of removing catalyst poisons derived from the cellulose-containing biomass.